The Heart And Its Diseases Essay Research

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The Heart And Its Diseases Essay, Research Paper The Heart and Its Diseases Cardiology has intrigued me since I was a small child. It has been my goal to become a cardiologist ever since the first grade. Cardiology is more than just studying the heart. To define it properly would be to say that cardiology is the study of the heart, its action, and its diseases (Clayman 52). The heart is located in the center of the chest, just behind the sternum, sitting in a hollow cavity between the lungs. The heart is slightly larger than your fist. It is about five inches long, three inches wide, and two inches thick. The heart is commonly represented in the familiar Valentine shape, but it actually resembles a grapefruit. The external features of the heart consist of the pericardium. The

function of the pericardium is to support and protect the heart. The inside of the pericardium is lined with a membrane that secrets a lubrication fluid which allows the pericardium to slide smoothly over the surface as the heart pumps. The internal features of the heart are quite a bit more complicated than the external features. The main features internally are the heart’s four hollow spaces, which are referred to as the chambers (Clayman 86). The pumping part of the heart consists of two very thin walled upper chambers, which are given the name atria. The two thick-walled lower chambers of the heart are called ventricles. The wall that divides the right side of the heart from the left is called the septum. The muscles in these walls of the chambers provide the pumping action

of the heart. These muscles cause the chamber to contract forcefully when the heart beats, which pushes blood through the body. The chambers of the heart can be divided into three layers. The most important of the three is the myocardium, which contains the muscles of the heart. The other two are called the endocardium and the epicardium. The heart has a left and right side, which contains these atriums and ventricles. There are four valves, which aid in the function of keeping blood flowing in the right direction (Katz 75). Two of these are known as the atrio-ventricular valves. These two are named the mitral valve and the tricuspid valve. These valves allow the blood to flow from each atrium into the corresponding ventricle. The mitral valve connects the left atrium to the left

ventricle, while the tricuspid connects the right atrium to the right ventricle. The other two valves in the heart allow blood to flow to the body from the ventricles but prevent blood from flowing backward into the ventricles from the body. These valves are known as the semilunar valves. They are named this because they are somewhat shaped like a crescent moon. The aortic semilunar valve allows blood to exit the left ventricle and enter the aorta. The aorta carries blood to the body tissues. The other valve is called the pulmonary similunar valve, which allows blood to exit the right ventricle and enter the pulmonary arteries. These arteries carry blood to the lungs to absorb oxygen, which is essential to our existence. These valves are designed to move blood in one direction

only, unless damaged by injury or disease. The heart can be viewed as a precisely designed two-stage pump. The first stage is the two atria, whose function is to ensure that the ventricles are fully inflated with blood. When this occurs, the ventricles contract to force blood out into the body. Although both sides of the heart contract at the same time, they have very different functions. The right side of the heart receives oxygen free blood from the body and pumps it to the lungs. The left side receives oxygen rich blood from the lungs and pumps it to the rest of the body (Katz 95). Each red blood cell passes through the heart twice on its way to tissues. The venae cavae aids in this process by returning the deoxygenated blood to the heart. The venae cavae is also the largest